Question

Which expression has a value of 90? (10 points)

a
3,600 ÷ 50
b
5,400 ÷ 60
c
6,400 ÷ 80
d
7,200 ÷ 90

Answer 1

b 5,400 ÷ 60

Explanation:

knoweth thay multiplication table.

what are the multiples of 9 ?

1×9 = 9

2×9 = 18

3×9 = 27

4×9 = 36

5×9 = 45

6×9 = 54

7×9 = 63

8×9 = 72

9×9 = 81

10×9 = 90

because multiples of 10 follow the same structure, we just add 0s.

so, the multiples of 90 are the same numbers as above, they just have a 0 at the end.

and if we also multiply the first numbers (1 ..10) by 10, the results get a second additional 0 at the end.

so, when we look at

3600

5400

6400

7200

we actually look at

36

54

64

72

36 = 4×9

so, 3600 has to be divided by 40 to result in 90.

but it is divided by 50. so, no.

54 = 6×9

so, 5400 has to be divided by 60 to result in 90.

and it is. so, yes ! 5400 ÷ 60 = 90

64 is no factor of 9 at all. so, no.

72 is 8×9

so, 7200 has to be divided by 80 to result in 90.

but it is divided by 90. so, no.

Answer 2

D

Explanation:

3x90=7200 ÷ by 3=90 that how you get it